The long-term goal of the proposed program is to overcome the problem of immunologic rejection of therapeutic allografts in man. Thus far this program as pertained almost entirely to human kidney transplantation. The main research aims are: (1) to apply advances in basic immunogenetics research to therapeutic tissue and organ transplantation in patients: (2) to improve thereby the success rate of such treatment; and (3) to utilize materials and information derived from patients to contribute to further immunogenetic advances. Emphasis presently is on utilizing leukocyte typing and other methods of histocompatibility testing and developing these methods to their full potential of clinical usefulness in the selection of compatible donors. The genetics of the HL-A locus is being studied in great detail, as well as the search for other loci which may be important in the cellular immunity and humoral immunity of graft rejection. A number of nonimmunologic studies of patients are also being pursued in this multidiscipline program as follows: chronic renal failure, hemodialysis, hypertension, immunopathology, rehabilitation of renal allograft recipients, and infections associated with immunosuppression.